4. PROGRAMS, MISSIONS, AND PAYLOADS

Life Sciences Research Objectives
To study blood pressure and flow responses in primates exposed to microgravity
To correlate other simultaneously recorded physiological information with cardiovascular results

The second Cosmos biosatellite mission with a primate payload was launched
on July 10, 1985. The biosatellite was recovered on July 17 after the 7-day
mission was completed. Mission parameters were very similar to those of Cosmos
1514. Countries participating in the mission included the U.S.S.R., the U.S.,
France, Czechoslovakia, the German Democratic Republic, Poland, Romania, Bulgaria,
and Hungary. The U.S. conducted a single cardiovascular experiment on one of
the two flight monkeys. Rats and other organisms were also flown, but no U.S.
experiments were conducted on those specimens.

Although the U.S.
experiment on the Cosmos 1667 mission was meant to be a repeat of the Cosmos
1514 cardiovascular experiment, several improvements were implemented on this
mission. Modified post-surgery animal handling procedures minimized the risk
of damaging the transducer implants. Data was sampled and recorded more frequently
during the in-flight period. Two monkeys with flight-type cardiovascular instrumentation
were studied in a ground-based synchronous control experiment; postflight cardiovascular
tests were not conducted after Cosmos 1514. Postural tilt tests were conducted
during the preflight and postflight periods in several animals to establish
a ground-based pool of normal data for this procedure. This data was compared
with the similar body fluid shifts thought to occur in flight. Instrument calibration
procedures were modified on this mission to ensure that blood pressure measurements
would be accurate.

U.S. Life Sciences Research Objectives

The main objective of U.S. participation in the Cosmos 1667 mission was to
measure carotid artery pressure and blood flow during the in-flight period.
The U.S. provided all flight and ground support instrumentation for this experiment.
Raw analog data from flight and ground control experiments were transferred
to the Cardiovascular Research Laboratory at ARC for analysis. Hemodynamic data
were to be correlated with concurrently recorded Soviet data. A similar correlative
study was performed during the Cosmos 1514 mission, where blood flow velocity
was compared to cardiac output as determined by impedance cardiography. Another
goal of the primate cardiovascular experiment on Cosmos 1667 was to use the
data obtained to estimate oxygen delivery capacity to the brain during space
flight. This procedure was postponed to a future mission because the external
carotid artery needed to be ligated to measure brain blood flow.

U.S. Life Sciences Payload

Organisms

Two rhesus monkeys(Macaca mulatta)named Gordyy and Oomka were flown onboard the biosatellite. Each animal
weighed approximately 4 kg. Both were instrumented for Soviet neurophysiology
studies. The instruments consisted of bilaterally implanted microelectrodes
in the vestibular nuclei, and electrooculogram and electroencephalogram electrodes.
The U.S. cardiovascular experiment was conducted on Gordyy, who was implanted
with a device to measure blood pressure and flow in the left common carotid
artery.

As in the Cosmos 1514 mission, monkeys were housed
in Soviet BIOS capsules. U.S. hardware developed for the Cosmos 1514 cardiovascular
experiment was used again on this mission. A barometric pressure recorder mounted
in the primate capsule was used to correct and normalize the implanted pressure
sensor to 760 mm of mercury.

*Amount actually consumed may be less. **A total of
400 grams of juice/day/monkey also available if all psychomotor tasks completed.
Table 4-9: Cosmos 1667 flight and control monkey experiments.

Two monkeys with cardiovascular instrumentation, Kvak and Samurai, were used
in a synchronous control experiment. A vivarium control experiment was also
carried out to determine the animals' responses in a non-stressed environment.
Orthostatic (tilt) tests were performed on Gordyy, Kvak, Samurai, and three
other animals with cardiovascular instrumentation. These tests were designed
to simulate the fluid shifts that occur in animals exposed to microgravity.

Cardiovascular instrumentation was implanted
in one flight animal and in two control animals about two months prior to the
flight. Tilt tests were performed on these animals during the preflight period.
Preflight data were also gathered on transducer cross calibration, control monitoring,
and bioengineering tests.

During the flight, 5-minute sampling periods
every 2 hours in the 16-hour "lights on" period provided carotid flow, carotid
pressure, ECG, time code, and ambient pressure data (Fig. 4-44). Data were sampled
for 5 minutes every 30 minutes during the "lights off" period.

Tilt tests were performed on the flight animal
with cardiovascular instrumentation (Gordyy) and one instrumented control animal
(Samurai) three days after flight. Both of these animals and one other control
animal (Kvak) participated in a ground-based synchronous control experiment
one month after the termination of the flight experiment. Tilt tests were again
performed, this time on Gordyy, Samurai, Kvak, and three others, after the synchronous
control experiment was completed. After all necessary tests had been performed,
the data were transferred from Soviet tape recorders to U.S. tape recorders.

Results

The experiment performed on this mission served to strengthen the data obtained
from the experiment conducted aboard Cosmos 1514. The most apparent cardiovascular
changes were a rapid initial decrease in heart rate followed by further decreases
upon continued exposure to the microgravity environment. The changes appeared
to be adaptive, and may have served to maintain an adequate supply of blood
to the brain during space flight.